JPS629623B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a hot-melt road surface coating paint with improved sedimentation and separation properties of aggregate. Heat-melting road surface coating paints have been used in recent years due to the increase in traffic volume and the development of road networks, because they can be easily and quickly worked without stopping vehicle traffic, and because of the pollution control aspect of removing solvents. The amount has increased significantly. Conventionally known hot-melt road surface coating paints include caking resins such as rosin, modified rosin, hydrocarbon resins, coumaron indene resins, and alkyd resins.
It contains a pigment, an aggregate, and if necessary, a plasticizer, an antioxidant, a weathering stabilizer, etc.
Therefore, hot-melt road coating paints are generally prepared through a process of putting these components into a melting pot, heating them, melting the caking resin, and then kneading them.
The method used for painting is to re-melt the material and then drip it onto the road surface through a slit in a coating machine.
For this reason, the melt viscosity of the coating material is adjusted to a range that allows these operations to be carried out easily. On the other hand, hot-melt road surface coating paints contain 70 to 85% by weight of pigment and aggregate as specified in JISK5665 in order to provide color and compressive strength to the paint film.
These pigments and aggregates often settle and separate when the melt viscosity of the paint is lowered to a level suitable for work in conventional hot-melt road coating paints due to the difference in specific gravity between the caking resin and the aggregate. Such sedimentation and separation of aggregates causes problems such as fluctuations in the composition of the paint during painting and, in extreme cases, clogging of the coating machine.
Conventionally, as a method of preventing sedimentation and separation of aggregate in such hot-melt paints, a method of blending a bulky inorganic compound such as finely powdered silica is known. However, in this method, the melt viscosity of the paint increases, resulting in a decrease in workability. The present invention was made in view of the above points, and as a result of intensive study, the present inventors discovered that the sedimentation and separability of aggregates could be improved by blending a specific hydrocarbon wax, and thus arrived at the present invention. This is what I did. That is, the present invention provides a hot-melt type road coating paint consisting of a caking resin, pigment, aggregate, etc., with a number average molecular weight of 500 to 100 parts by weight, based on 100 parts by weight of the caking resin.
10,000 and a product of acid value and number average molecular weight of 40,000 or more, a carboxyl group-containing hydrocarbon wax copolymerized with an unsaturated carboxylic acid or its anhydride.
This is a melt-type road surface coating paint characterized by containing 0.01 to 20 parts by weight. The caking resin used in the present invention includes:
Examples include rosin, modified rosin, coumaron indene resin, hydrocarbon resin, terpene resin, polyester resin, and the like. The modified hydrocarbon wax used in the present invention, which will be described later, exhibits an excellent effect when, among the above-mentioned caking resins, a hydrocarbon resin that tends to cause aggregate sedimentation and separation is used. In addition, the hydrocarbon resin in the present invention is produced by thermal decomposition of petroleum and has a boiling point of -10
A resin obtained by polymerizing any fraction between 280°C and 280°C using a Friedel-Crafts catalyst, and a pure monomer capable of cationically polymerizing up to 50% by weight with the above fraction, such as isobutylene, butadiene, isoprene, piperylene, etc. It can be obtained by copolymerizing unsaturated aliphatic compounds, unsaturated alicyclic compounds such as dicyclopentadiene, or unsaturated aromatic compounds such as styrene, vinyltoluene, isopropenyltoluene, α-methylstyrene, and indene using the same method. or resins obtained by cationic polymerization or radical polymerization of only the above-mentioned unsaturated aromatic compounds, and furthermore, resins obtained by hydrogenating these resins. Among these, the boiling point under normal pressure produced by thermal decomposition of petroleum is -10℃ to
A so-called aliphatic petroleum resin obtained by polymerizing a 60° C. fraction using a Friedel-Crafts catalyst is preferable because it has excellent heat resistance and hue. The hydrocarbon resin obtained by the above method is solid at room temperature and has a number average molecular weight of 500 or more.
3000, preferably 700 to 2000;
Softening point (ring and ball method) of 60 to 150℃, preferably
70 to 120℃, hue (Gardner, resin
100%) is 10 or less, preferably 8 or less. These hydrocarbon resins as they are, when a large amount of aggregate is blended as in the composition of the present invention,
Since the fluidity when melted is poor and the coating workability is poor, it is preferable to modify it by introducing a carboxyl group. As a method of introducing a carboxyl group, a method of oxidizing a hydrocarbon resin or a method of grafting an unsaturated carboxylic acid or its anhydride can be adopted. Oxidation of the hydrocarbon resin can be carried out, for example, by blowing an oxygen-containing gas such as oxygen or air into the molten resin while stirring it.
In this case, it is possible to shorten the reaction time by using a radical initiator, but it is not necessary to use a radical initiator. A method for grafting an unsaturated carboxylic acid onto a hydrocarbon resin includes heating the hydrocarbon resin and the unsaturated carboxylic acid to an elevated temperature, for example, in the presence or absence of a solvent, with or without the addition of a radical initiator. It is done by certain things. Examples of the unsaturated carboxylic acid or its anhydride to be grafted onto the hydrocarbon resin include acrylic acid, methacrylic acid,
Examples include fumaric acid, maleic acid, itaconic acid, citraconic acid, maleic anhydride, citraconic anhydride, and itaconic anhydride. Among these, maleic anhydride is preferred. The modified hydrocarbon resin thus obtained has an acid value of 0.1
It is preferably in the range of 1 to 25, particularly 1 to 20. If the acid value is 0.1 or less, the fluidity of the composition during melting will be low, and if it is 25 or more, the hue of the modified hydrocarbon resin will deteriorate, which is not preferable. Note that it is also effective to react the carboxyl group-containing modified hydrocarbon resin obtained by the above method with an alcohol to introduce an ester bond. In this case, thermal stability at high temperatures is improved.
Alcohols include methanol, ethanol, propanol, butanol, octanol,
Monohydric alcohols such as glycidyl alcohol and alkylene glycol monoalkyl ether, and polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, and glycerin can be used. obtained by heating. The carboxyl group-containing hydrocarbon wax used as an aggregate anti-settling agent in the present invention can be prepared by grafting an unsaturated carboxylic acid or its anhydride onto the hydrocarbon wax, or by grafting ethylene or α-olefin with an unsaturated carboxylic acid or its anhydride. It is obtained by radical copolymerization of anhydride under 100 to 1000 atmospheres in the coexistence of a chain transfer agent. In addition, in place of unsaturated carboxylic acid or its anhydride, unsaturated carboxylic acid esters are copolymerized and hydrolyzed,
It may also be a carboxylic acid. Hydrocarbon waxes used as raw materials for graft-modified hydrocarbon waxes include, for example, polyethylene waxes, polypropylene waxes, polyolefin waxes such as ethylene-propylene copolymer waxes, microcrystalline waxes, Fischer Tropic waxes, etc. can be mentioned. Examples of the unsaturated carboxylic acid or anhydride thereof to be copolymerized include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid,
Examples include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, and the like. Among these, maleic anhydride is the most suitable. As a method for grafting these unsaturated carboxylic acids or their anhydrides onto the above-mentioned hydrocarbon wax, a known method is used in which graft addition is carried out using a radical initiator at a reaction temperature higher than the decomposition temperature in the presence or absence of a solvent. methods are available. Solvents include halogenated hydrocarbons, benzene,
Alkylbenzenes, linear saturated aliphatic hydrocarbons are preferred. As the radical initiator, acyl peroxides, peresters, and dialkyl peroxides are suitable, and among them, dialkyl peroxides are most suitable. Benzoyl peroxide, t-butyl peroxybenzoate, t-butylcumyl peroxide, di-t-butyl peroxide, dicumyl peroxide, α・α′-di(t-butylperoxy)1,4-diisopropylbenzene, 2・5-
Dimethyl-2,5-di(t-butylperoxy)
Hexyne-3,2,5-dimethyl-2,5-di(t-butylperoxy)hexane can be exemplified. The use of solvents reduces the viscosity of hydrocarbon waxes,
Although it is used as appropriate for the purpose of purifying the reactant following the reaction, it is not necessary to use a solvent in order to obtain the unsaturated carboxylic acid-modified hydrocarbon wax that is the object of the present invention. Unsaturated carboxylic acids or their anhydrides are used singly or in combination of two or more, and the amount used is adjusted depending on the degree of modification of the modified product or the presence or absence of a solvent; Usually 0.5 to 30 parts by weight are used. The radical initiator is usually used in an amount of 0.03 to 20 mmol per 100 parts by weight of the hydrocarbon wax. The reaction temperature is usually 100 to 300℃, but 120℃
C. to 200.degree. C. is preferred. The reaction time is usually 1 minute to 5 hours, and the higher the reaction temperature, the shorter the reaction time. However, the higher the reaction temperature or the higher the degree of modification, the worse the hue becomes, so the reaction temperature should be determined based on these considerations. The unsaturated carboxylic acid or its anhydride and the radical initiator may be added all at once at the beginning of the reaction, but it is preferable to continuously supply both to the reaction system at a rate that corresponds to the graft addition rate of the reaction system. . The reaction format may be batchwise or continuous. The reaction product may be used after being purified by removing the reaction solvent, monomer and initiator. Among the carboxyl group-containing hydrocarbon waxes obtained by the above method, those that can be used in the present invention include:
Number average molecular weight is 500 to 10000, preferably 700
4000 to 4000, especially 800 to 3000, and the product of number average molecular weight and acid value is 40000 or more, preferably
50,000 or more, especially in the range of 60,000 to 337,000. Carboxyl group-containing hydrocarbon waxes with a number average molecular weight of less than 500 have a low aggregate settling prevention effect, and waxes with such molecular weights are volatile under melt-mixing conditions and have a low melting point, so the softening point of the paint may be low. It has drawbacks such as a decrease in mechanical strength and a decrease in mechanical strength. On the other hand, hydrocarbon waxes containing carboxyl groups exceeding 10,000 not only have poor compatibility with the above-mentioned caking resin but also significantly increase the melt viscosity of the paint. However, a large amount of fluidity improver must be added, and the anti-settling properties of the aggregate are not improved. The reason why the product of number average molecular weight and acid value must be 40,000 or more is that the aggregate sedimentation prevention effect of carboxyl group-containing hydrocarbon wax is statistically 0.7 per molecule of hydrocarbon wax.
This is because it can only be obtained when there are at least 0.9 carboxyl groups, preferably at least 0.9 carboxyl groups.
The greater the number of carboxyl groups per molecule of hydrocarbon wax, the better the effect of preventing aggregate settling. However, introducing too many carboxyl groups into a hydrocarbon wax not only has the disadvantage of increasing the melt viscosity of the wax and increasing the viscosity during painting operations, but also causes the product to become colored due to side reactions. Therefore, the number of carboxyl groups per molecule is within 6 (the product of average molecular weight and acid value is 337,000 or less)
It is preferable that In particular, the number average molecular weight
Carboxyl group-containing hydrocarbon waxes with a molecular weight of 800 to 3,000 and a product of number average molecular weight and acid value of 60,000 or more have the effect of lowering the melt viscosity of paints, and exhibit excellent aggregate sedimentation prevention effects when mixed in small amounts. Most preferred. The number average molecular weight (Mn) of the hydrocarbon wax in the present invention is measured by a boiling point elevation method using a toluene solution as a sample. Measurement was carried out using Epriometer L-4 type (manufactured by Takara Kogyo Co., Ltd., device constant k = 3.33).
×10 ^-3 ). Acid value is measured by potassium hydroxide neutralization method. The method is to add 0.5g of the sample to an aromatic hydrocarbon solvent (trade name, Mitsui Solvent Special, boiling point 163-178), each molecule of which has 9 carbon atoms.
℃, specific gravity 0.88, dissolved in a mixed solvent of 90 ml (manufactured by Mitsui Petrochemical Industries, Ltd.) and 10 ml of dimethyl sulfoxide (Wako Pure Chemical Industries, Ltd.) at 100 to 130 ℃, and 0.1N-KOH
This is a neutralization titration method using ethanol solution and phenolphthalein as an indicator. The acid value is expressed as the number of mg of KOH required for the above neutralization. Although it is not clear why the carboxyl group-containing hydrocarbon wax used in the present invention has the effect of improving the sedimentation and separability of aggregate without substantially increasing the melt viscosity during the coating process, By blending a carboxyl group-containing hydrocarbon wax, the melt viscosity of the paint becomes extremely high at low shear rates, so the carboxyl groups introduced into the wax molecules have some kind of interaction with the aggregate, making it difficult for the paint to stand still. Sometimes, the formation of a thixostructure due to this interaction prevents the sedimentation and separation of the aggregate, and under the shearing force during painting, this thixostructure disappears, and the inherent lubricating properties of wax molecules are expressed, and the viscosity of the paint must be increased. It is presumed that it has a similar function. The shear rate during operation is typically 10 ² sec ^-1
or 10 ⁴ sec ^-1 . In the paint of the present invention, the carboxyl group-containing hydrocarbon wax is 0.01 parts by weight per 100 parts by weight of the caking resin.
It is necessary to add 20 parts by weight, preferably 0.05 to 10 parts by weight, particularly 0.1 to 2 parts by weight. If the amount of carboxyl group-containing hydrocarbon wax is too small, the effect of improving aggregate sedimentation and separability cannot be obtained, and on the other hand, if it is too large, the compressive strength of the coating film will decrease, which is not preferable. In addition to the caking resin and carboxyl group-containing hydrocarbon wax, the hot-melt road surface coating paint of the present invention includes:
It contains a pigment and an aggregate as essential components, and further contains an antioxidant, a weathering stabilizer, a plasticizer, a fluidity improver, a flexibility improver, glass beads, etc. as necessary. Examples of the aggregate used in the present invention include calcium carbonate, silica sand, talc, and calcium sulfate. Pigments for coloring paints include any pigments used in regular paints,
For example, organic and inorganic pigments such as titanium white, red iron, zinc white, yellow lead, phthalocyanine blue, and carbon black can be used. Usually 200 to 700 parts by weight, preferably 400 to 600 parts by weight, per 100 parts by weight of the caking resin of these aggregates and pigments.
It is blended within the range of parts by weight. As the antioxidant, known phenolic antioxidants, phosphate ester antioxidants, and the like can be used. Examples of the plasticizer include vegetable oil, mineral oil, polybutene, liquid paraffin, phthalate ester, and polyalkylene glycol. Examples of the fluidity improver include unmodified paraffin wax, microcrystalline wax, polyethylene wax, and the like. Examples of coating film flexibility improvers include polymers such as ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, polyolefin, ethylene-α-olefin copolymer, atactic polypropylene, and polyisobutylene. Compounds can be mentioned. The method for preparing the road surface coating paint of the present invention includes a method in which components such as a caking resin and a carboxyl group-containing hydrocarbon wax are melted, and then aggregate and pigment are blended with stirring, and a method in which all components are mixed and then dissolved. The following methods can be mentioned. Furthermore, the paint of the present invention can be easily applied using a conventional hot-melting road surface coating application machine. The heat-melting type road surface coating paint of the present invention has excellent workability, so it is easy to apply and has significantly improved aggregate settling and separation properties. Since no sedimentation and separation occurs, there is no clogging of painting equipment. Even if glass beads, cut glass, etc. are sprinkled on the coating film immediately after painting, the amount of spraying can be reduced because these substances do not get immersed in the coating film. Furthermore, the resulting coating film has good performance in terms of strength, gloss, heat resistance, etc. Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples unless the gist thereof is exceeded. Example 1 (1) Preparation of paint raw materials (a) Carboxyl group-containing hydrocarbon wax Low molecular weight polyethylene with a number average molecular weight of 700
7 parts by weight of maleic anhydride per 100 parts by weight of a
Di-t-butyl peroxide as initiator
0.4 parts by weight was added dropwise to low molecular weight polyethylene under stirring at 160°C in a nitrogen atmosphere over a period of 1 hour, and the reaction was further carried out for 2 hours to obtain maleic acid modified low molecular weight polyethylene A (number average molecular weight 950, An acid value of 70) was obtained. (b) Caking resin Aliphatic hydrocarbon resin (product name Hiretsu P)
−100L, manufactured by Mitsui Petrochemical Industries, softening point 97
℃, number average molecular weight 1620) was melted at 210℃,
Maleic anhydride was added under stirring and reacted for 1 hour to obtain a maleic acid graft-modified hydrocarbon resin having a softening point of 98° C. and an acid value of 4.8. (2) Preparation of hot-melt road coating paint For the hot-melt road coating paint, each component was weighed out at the mixing ratio shown below and thoroughly mixed. Next, this was heated and melted at a temperature of 190°C, and the mixture was thoroughly stirred for 30 minutes. Caking resin 100 parts by weight Plasticity (Mineral oil manufactured by Sunoil Co., Ltd., blend of 20% by weight and 80% by weight of Sansen 4240 and Sunper 115, respectively)
7 parts by weight of calcium carbonate (Whiten H, manufactured by Shiraishi Calcium Co., Ltd.) 180 parts by weight of Kansui sand (#30, manufactured by Nitto Funka Co., Ltd.) 215 parts by weight of titanium white (Taipeku A-220, manufactured by Ishihara Sangyo Co., Ltd.)
60 parts by weight glass beads (UB-108L manufactured by Union Glass Industries)
100 parts by weight Carboxyl group-containing hydrocarbon wax 5 parts by weight (3) Evaluation method

【table】

[Table] (iv) Fluidity of hot-melt road coating paint adjusted with (2)
Melt and stir at 200℃, using a metal ladle (31mmφ,
A portion of it was quickly scooped up (to a depth of 24 mm) and poured onto a smooth aluminum plate from a height of 30 mm. The major axis (a) and minor axis (b) of the composition that hardened into a disk shape were measured, and the average value [(a+
b)/2] was defined as the fluidity. (v) 50% of the heat-melting road coating paint adjusted according to (2)
The mixture was filled into a ml beaker, left to stand at 240°C for 2 hours, cooled and hardened, cut vertically, and expressed as the sedimentation rate (%) of the aggregate on the cut surface. (vi) Observe the surface of the disk that was subjected to the luster flow test. Those with good gloss are marked as ○, and those with slightly poor gloss are marked as △.
Lack of luster was marked as ×. Examples 2 to 5 The hot-melt road coating paint of Example 1 was prepared in the same manner as in Example 1, except that the amount of carboxyl group-containing hydrocarbon wax was changed as shown in Table 1. Examples 6 to 8 In the preparation of the carboxyl group-containing hydrocarbon wax of Example 1, a number average molecular weight of 1250 was used as a raw material.
A maleic acid-modified low molecular weight polyethylene B having a number average molecular weight of 1,550 and an acid value of 28 was prepared in the same manner except that the low molecular weight polyethylene B of 1.0 was used and the amount of maleic anhydride was changed. The same procedure as in Examples 1 to 3 was carried out except that this modified low molecular weight polyethylene B was used instead of modified low molecular weight polyethylene A. Comparative Example 1 The coating material of Example 1 was prepared in the same manner as in Example 1 except that the formulation did not contain a carboxyl group-containing hydrocarbon wax. The results of Examples 1 to 8 and Comparative Example 1 are shown in Table 1.

[Table] Example 9 In preparing the carboxyl group-containing hydrocarbon wax in Example 1, the amount of maleic anhydride charged was changed to prepare maleic acid-modified low molecular weight polyethylene C having a number average molecular weight of 1350 and an acid value of 110.
The same procedure as in Example 3 was carried out except that this modified low molecular weight polyethylene C was used instead of the modified low molecular weight polyethylene A. Comparative Example 2 Modified low molecular weight polyethylene A in Example 1
Example 3 was carried out in the same manner as in Example 3, except that low molecular weight polyethylene a, which was the raw material for , was used instead of modified low molecular weight polyethylene A. Examples 10 to 12, Comparative Examples 3 and 4 In the preparation of the carboxyl group-containing hydrocarbon wax in Example 8, the amount of maleic anhydride charged was changed and the maleic acid-modified low molecular weight polyethylenes D and E shown in Table 2 were prepared. , F, G, and H were prepared. The same procedure as in Example 8 was carried out except that these maleic acid-modified low molecular weight polyethylenes were used in place of maleic acid-modified low molecular weight polyethylene B. Comparative Example 5 Modified low molecular weight polyethylene B in Example 8
Example 8 was carried out in the same manner as in Example 8, except that low molecular weight polyethylene B, which was the raw material for the modified low molecular weight polyethylene B, was used instead of the modified low molecular weight polyethylene B. The results of Examples 9 to 12 and Comparative Examples 2 to 5 are shown in Table 2.

[Table] Examples 13, 14 In the preparation of the carboxyl group-containing hydrocarbon wax of Example 1, a number average molecular weight of 1800 was used as a raw material.
Modified low molecular weight polyethylenes I and J shown in Table 3 were prepared using low molecular weight polyethylene C shown in Table 3 and varying the amount of maleic anhydride. Example 3 except that these modified low molecular weight polyethylenes I and J were used in place of modified low molecular weight polyethylene A.
I went in the same way. Comparative Example 6 Modified low molecular weight polyethylene I in Example 13
Example 13 was carried out in the same manner as in Example 13, except that low molecular weight polyethylene C, which was the raw material for , was used instead of modified low molecular weight polyethylene I. Comparative Examples 7 to 9 The same procedures as Examples 1 to 3 were carried out, except that fine powder silica (trade name Aerosil #384, manufactured by Nippon Aerosil) was used instead of modified low molecular weight polyethylene A. The results of Examples 13-14 and Comparative Examples 6-9 are shown in Table 3.

[Table] Example 15 The same procedure as in Example 1 was carried out except that an aliphatic hydrocarbon resin (trade name: Hiretsu P-100L, hereinafter referred to as caking resin B) was used as the caking resin. Comparative Example 10 The same procedure as in Example 15 was carried out except that low molecular weight polyethylene b was used instead of modified low molecular weight polyethylene A. Comparative Example 11 The same procedure as in Example 15 was carried out except that modified low molecular weight polyethylene A was not blended. The results of Example 15 and Comparative Examples 10 to 11 are shown in Table 4.

[Table] Examples 16 to 18 In the preparation of the hot-melt road coating paint of Example 1, ethylene-acrylic acid copolymer wax (manufactured by Allied Chemical Co., Ltd., trade name AC Polyethylene 580) was used instead of maleic acid-modified low molecular weight polyethylene A. )
Example 1 except that K is used in the amount shown in Table 5.
I went in the same way. The results of Examples 16 to 18 are shown in Table 5.

【table】

Claims (1)

[Scope of Claims] 1. A hot-melt type road coating paint consisting of a caking resin, pigment, aggregate, etc., which has a number average molecular weight of 500 to 10,000 and an acid value and a number average molecular weight based on 100 parts by weight of the caking resin. 1. A hot-melt road surface coating paint characterized by containing 0.01 to 20 parts by weight of a carboxyl group-containing hydrocarbon wax copolymerized with an unsaturated carboxylic acid or its anhydride having a product of 40,000 or more. 2. The paint according to claim 1, wherein the caking resin is a hydrocarbon resin. 3. The paint according to claim 2, wherein the hydrocarbon resin is an aliphatic petroleum resin. 4. The paint according to claim 2, wherein the hydrocarbon resin is a carboxyl group-containing modified hydrocarbon resin or a reaction product of the modified hydrocarbon resin and an alcohol. 5. The paint according to claim 4, wherein the modified hydrocarbon resin has an acid value in the range of 1 to 20. 6. The paint according to claim 1, wherein the amount of the carboxyl group-containing hydrocarbon wax is in the range of 0.01 to 2 parts by weight per 100 parts by weight of the caking resin. 7. The paint according to claim 1, wherein the carboxyl group-containing hydrocarbon wax is a hydrocarbon wax grafted with an unsaturated carboxylic acid or its anhydride. 8. The paint according to claim 1 or 7, wherein the hydrocarbon wax is a polyolefin wax. 9 Claim 8, characterized in that the polyolefin wax is polyethylene wax
Paints listed in section. 10. The paint according to claim 7, wherein the unsaturated carboxylic acid anhydride is maleic anhydride. 11. The paint according to claim 1, wherein the aggregate and pigment are blended in an amount of 200 to 700 parts by weight based on 100 parts by weight of the caking resin.